1. Field of the Invention
This invention relates to analysis of integrated circuit devices and, more particularly, to protection of device pins during that analysis.
2. Description of the Related Art
In order to analyze packaged integrated circuit devices, to determine, for example, the nature and causes of a device failure, it is often necessary to remove a portion of the package in which the integrated circuit resides in order to gain access to the integrated circuit contained within the integrated circuit package. Such a process is known as a device "decapsulation" or "decapping" process. For integrated circuits packaged in plastic packages, in order to remove a portion of a package, the decapsulation process uses nitric acid to etch away a portion of the plastic package. However, the leads of the packaged device may be damaged by exposure to the nitric acid utilized in the decapping process. The nitric acid can cause the leads to disintegrate rendering the part untestable. In addition, the nitric acid can caused the leads to be oxidized to the extent that the leads require cleaning before the part may be tested. High pin count devices, such as those that may be packaged in, e.g., thin quad flat packs (TQFPs), are very susceptible to such damage.
In addition to the problems associated with exposure to nitric acid, as device pin counts increase and device sizes continue to decrease, the leads or pins of the devices have become less tolerable to handling and, thus, there is an increased likelihood of deforming the device pins and rendering the part untestable when the part is subject to the decapping process. That is, as device pin counts continue to grow and geometries continue to shrink, device pins have become more fragile. It would be desirable to provide a way to protect the device leads from the nitric acid employed during the decapping process as well as make the device pins less susceptible to deformation during the decapping process.